Backlight unit and display apparatus having the same

ABSTRACT

A display apparatus includes a light guide plate, a light source unit and a display panel. The light guide plate includes an incident surface, an exit surface and an opposite surface opposite to the exit surface and guides a light incident into the incident surface toward the exit surface. The light source unit includes a light source which generates light and is disposed adjacent to the incident and has an emitting surface inclined with respect to the incident surface. An extension line of a normal line of the emitting surface passes through the opposite surface, and the light is incident into the incident surface while being inclined toward the opposite surface. The display panel displays an image by receiving the light emitted from the exit surface.

This application is a continuation application of U.S. application Ser.No. 13/191,834 filed Jul. 27, 2011, which claims priority to KoreanPatent Application No. 10-2011-0011147 filed on Feb. 8, 2011, and allthe benefits accruing therefrom under 35 U.S.C. §119, the contents ofwhich are herein incorporated by reference in their entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a backlight unit and a display apparatus havingthe same. More particularly, the invention relates to a backlight unitcapable of preventing light leakage while improving the light incidentefficiency from a light source to a light guide plate, and a displayapparatus having the same.

2. Description of the Related Art

In general, a display apparatus includes a backlight unit to generate alight and a display panel to display the image by using the light.

A display apparatus for a notebook computer or a mobile device includesan edge-illumination type backlight unit having a light source, and alight guide plate to guide a light generated from the light source to adisplay panel. In addition, in the edge-illumination type backlightunit, the light source is positioned adjacent to an edge of the lightguide plate to supply the light toward the light guide plate so that thelight is guided to the display panel by the light guide plate.

BRIEF SUMMARY OF THE INVENTION

An exemplary embodiment of the invention provides a backlight unitcapable of reducing or effectively preventing light leakage whileimproving the light incident efficiency from a light source to a lightguide plate.

An exemplary embodiment of the invention also provides a displayapparatus having such a backlight unit.

In one exemplary embodiment, a backlight unit includes a light guideplate and a light source unit.

The light guide plate includes an incident surface, an exit surface andan opposite surface opposite to the exit surface, and guides a lightincident into the incident surface toward the exit surface. The lightsource unit includes a light source which generates light and isdisposed adjacent to the incident surface and has an emitting surfaceinclined with respect to the incident surface. An extension line of anormal line of the emitting surface passes through the opposite surface,and the light is incident into the incident surface while being inclinedtoward the opposite surface.

In another exemplary embodiment, a display apparatus includes a lightguide plate, a light source unit and a display panel.

The light guide plate includes an incident surface, an exit surface andan opposite surface opposite to the exit surface, and guides a lightincident into the incident surface toward the exit surface. The lightsource unit includes a light source which generates light and isdisposed adjacent to the incident surface and has an emitting surfaceinclined with respect to the incident surface. An extension line of anormal line of the emitting surface passes through the opposite surface,and the light is incident into the incident surface while being inclinedtoward the opposite surface. The display panel displays an image usingthe light emitted from the exit surface.

According to the exemplary embodiments of the backlight unit and thedisplay apparatus having the same, the emitting surface of the lightsource is inclined with respect to the incident surface of the lightguide plate so that the light emitted from the light source is suppliedto the incident surface while being inclined with respect to theopposite surface of the light guide plate. Thus, direct emission of thelight to the display panel from the light source can be reduced oreffectively prevented. That is, light leakage can be reduced oreffectively prevented, and the light incident efficiency, which is aratio of the light incident into the light guide plate to the lightemitted from the light source, can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other advantages of the invention will become readilyapparent by reference to the following detailed description whenconsidered in conjunction with the accompanying drawings wherein:

FIG. 1 is an exploded perspective view showing an exemplary embodimentof a display apparatus according to the invention;

FIG. 2 is an exploded perspective view showing the relationship amongfirst to third light source parts, a light guide plate and a diffusionplate shown in FIG. 1;

FIG. 3A is a perspective view of an exemplary embodiment of the firstlight source part shown in FIG. 2;

FIG. 3B is an enlarged side cross-sectional view showing therelationship between the first light source part shown in FIG. 3A andthe light guide plate;

FIG. 4 is an enlarged cross-sectional view of another exemplaryembodiment of a light source part shown in FIG. 1 according to theinvention;

FIG. 5 is an enlarged cross-sectional view of another exemplaryembodiment of a light source part shown in FIG. 1 according to theinvention;

FIG. 6A is a front perspective view of another exemplary embodiment of alight source unit shown in FIG. 1 according to the invention;

FIG. 6B is a rear perspective view of the light source unit shown inFIG. 6A;

FIG. 7A is a front perspective view of still another exemplaryembodiment of a light source unit shown in FIG. 1 according to theinvention;

FIG. 7B is a rear perspective view of the light source unit shown inFIG. 7A;

FIG. 8 is a cross-sectional view showing a light source unit of FIGS. 7Aand 7B mounted on a printed circuit board;

FIG. 9 is an exploded perspective view showing another exemplaryembodiment of the relationship among the first to third light sourceparts, the light guide plate and the diffusion plate according to theinvention; and

FIG. 10 is a side cross-sectional view showing the light source partshown in FIG. 9.

DETAILED DESCRIPTION OF THE INVENTION

The invention is described more fully hereinafter with reference to theaccompanying drawings, in which exemplary embodiments of the inventionare shown. This invention may, however, be embodied in many differentforms and should not be construed as limited to the exemplaryembodiments set forth herein. Rather, these embodiments are provided sothat this disclosure will be thorough and complete, and will fullyconvey the scope of the invention to those skilled in the art. In thedrawings, the size and relative sizes of layers and regions may beexaggerated for clarity.

It will be understood that when an element or layer is referred to asbeing “on,” “connected to” or “coupled to” another element or layer, theelement or layer can be directly on, connected or coupled to anotherelement or layer or intervening elements or layers. In contrast, when anelement is referred to as being “directly on,” “directly connected to”or “directly coupled to” another element or layer, there are nointervening elements or layers present. As used herein, “connected”includes physically and/or electrically connected. Like numbers refer tolike elements throughout. As used herein, the term “and/or” includes anyand all combinations of one or more of the associated listed items.

It will be understood that, although the terms first, second, third,etc., may be used herein to describe various elements, components,regions, layers and/or sections, these elements, components, regions,layers and/or sections should not be limited by these terms. These termsare only used to distinguish one element, component, region, layer orsection from another region, layer or section. Thus, a first element,component, region, layer or section discussed below could be termed asecond element, component, region, layer or section without departingfrom the teachings of the invention.

Spatially relative terms, such as “lower,” “upper” and the like, may beused herein for ease of description to describe the relationship of oneelement or feature to another element(s) or feature(s) as illustrated inthe figures. It will be understood that the spatially relative terms areintended to encompass different orientations of the device in use oroperation, in addition to the orientation depicted in the figures. Forexample, if the device in the figures is turned over, elements describedas “lower” relative to other elements or features would then be oriented“upper” relative to the other elements or features. Thus, the exemplaryterm “lower” can encompass both an orientation of above and below. Thedevice may be otherwise oriented (rotated 90 degrees or at otherorientations) and the spatially relative descriptors used hereininterpreted accordingly.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a,” “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof.

Embodiments of the invention are described herein with reference tocross-section illustrations that are schematic illustrations ofidealized embodiments (and intermediate structures) of the invention. Assuch, variations from the shapes of the illustrations as a result, forexample, of manufacturing techniques and/or tolerances, are to beexpected. Thus, embodiments of the invention should not be construed aslimited to the particular shapes of regions illustrated herein but areto include deviations in shapes that result, for example, frommanufacturing.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this invention belongs. It will befurther understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art andwill not be interpreted in an idealized or overly formal sense unlessexpressly so defined herein.

Hereinafter, the exemplary embodiments of the invention will bedescribed in detail with reference to accompanying drawings.

FIG. 1 is an exploded perspective view showing an exemplary embodimentof a display apparatus according to the invention.

Referring to FIG. 1, the display apparatus 500 includes a backlight unit200, a display panel 400, a bottom chassis 310 and a top chassis 380.

The backlight unit 200 includes a first light source part 20, a secondlight source part 26, a third light source part 29, a light guide plate10 having a first sub-light guide plate 11 and a second sub-light guideplate 16, a diffusion member 30, a reflective plate 110, a diffusionplate 120 and optical sheets 130.

The first to third light source parts 20, 26 and 29 generate lightrequired for the display apparatus 500 to display an image. The lightguide plate 10 guides the light generated from the first to third lightsource parts 20, 26 and 29 toward the display panel 400.

The relationship among the first to third light source parts 20, 26 and29 and the first and second sub-light guide plates 11 and 16 and thetraveling route of the light generated from each light source part areas follows.

The first light source part 20 is provided between the first and secondsub-light guide plates 11 and 16 so that the light generated from thefirst light source part 20 is supplied toward the first and secondsub-light guide plates 11 and 16. In addition, the second light sourcepart 26 faces the first light source part 20 while interposing the firstsub-light guide plate 11 therebetween so that the light generated fromthe second light source part 26 is supplied toward the first sub-lightguide plate 11. The third light source part 29 faces the first lightsource part 20 while interposing the second sub-light guide plate 16therebetween so that the light generated from the third light sourcepart 29 is supplied toward the second sub-light guide plate 16.

According to one embodiment of the invention, the first to third lightsource parts 20, 26 and 29 can be individually driven, so that thelights generated from the first to third light source parts 20, 26 and29 may have intensities different from each other and can be supplied tothe first and second sub-light guide plates 11 and 16, independently.Thus, the intensity of the light supplied to the display panel 400through the first and second sub-light guide plates 11 and 16 may varydepending on image display regions of the display panel 400. That is,the display apparatus 500 can be driven through the local dimmingscheme.

The diffusion member 30 is provided between the first and secondsub-light guide plates 11 and 16 to cover the first light source part20, thereby diffusing the light that travels toward the display panel400 by passing through and between the first and second sub-light guideplates 11 and 16.

The reflective plate 110 includes a material capable of reflecting thelight, such as polyethylene terephthalate (“PET”) or aluminum. Thereflective plate 110 is provided on a bottom portion 311 of the bottomchassis 310 to reflect the light generated from the first to third lightsource parts 20, 26 and 29. As a result, the reflective plate 110increases the intensity of the light supplied toward the display panel400.

The diffusion plate 120 is disposed between the light guide plate 10 andthe display panel 400. The diffusion plate 120 diffuses the light outputfrom the light guide plate 10 and the light that has been diffused bythe diffusion member 30. As a result, the intensity of the light in aunit area of the display panel 400 may be more uniform due to thediffusion plate 120.

According to one embodiment of the invention, the diffusion plate 120 isplaced on support members 40 protruding from the light guide plate 10,and the diffusion plate 120 is spaced apart from the light guide plate10 by the support members 40.

The optical sheets 130 are provided between the display panel 400 andthe diffusion plate 120. The optical sheets 130 may include prism sheetsto improve the front brightness by collecting the light output from thediffusion plate 120, and/or diffusion sheets to diffuse the light outputfrom the diffusion plate 120.

According to one embodiment of the invention, the display panel 400 maybe a liquid crystal display panel that displays the image by receivingthe light generated from the backlight unit 200. The display panel 400includes a first substrate 410, a second substrate 420 facing the firstsubstrate 410 and liquid crystals (not shown) interposed between thefirst and second substrates 410 and 420.

According to one embodiment of the invention, the first substrate 410includes a plurality of pixel electrodes (not shown), and a plurality ofthin film transistors electrically connected to the pixel electrodes.Each thin film transistor switches a driving signal supplied to eachpixel electrode. In addition, the second substrate 420 includes colorfilter layers corresponding to the pixel electrodes in one-to-onecorrespondence, and an opposite electrode that generates the electricfield together with the pixel electrodes to control the alignment of theliquid crystals.

A printed circuit board 430 is provided at one side of the display panel400 to output the driving signal to the display panel 400. The printedcircuit board 430 is connected to the display panel 400 through aplurality of tape carrier packages (“TCP”) 431, and a plurality ofdriving chips 432 are mounted on the TCP 431.

Each driving chip 432 may have a data driver (not shown) therein tooutput a data signal to the display panel 400. A gate driver (notshown), which outputs a gate signal to the display panel 400, can bedirectly on the display panel 400 through a thin film process. Inaddition, the driving chips 432 may be mounted on the display panel 400in the form of chip on glass (“COG”). In this case, the driving chips432 can be integrated in one chip.

The bottom chassis 310 includes the bottom portion 311 and sidewalls 312extending from the bottom portion 311 so that a receiving space isdefined in the bottom chassis 310 to receive the backlight unit 200 andthe display panel 400. In addition, the top chassis 380 is coupled withthe bottom chassis 310 in such a manner that the backlight unit 200 andthe display panel 400 can be stably fixed in the bottom chassis 310.

FIG. 2 is an exploded perspective view showing the relationship amongthe first to third light source parts 20, 26 and 29, the light guideplate 10 and the diffusion plate 120 shown in FIG. 1, FIG. 3A is aperspective view of the first light source part shown in FIG. 2, andFIG. 3B is an enlarged side cross-sectional view showing therelationship between the first light source part shown in FIG. 3A andthe light guide plate 10.

Referring to FIG. 2, the light guide plate 10 includes the first andsecond sub-light guide plates 11 and 16 spaced apart from each other andaligned in the first direction D1. The diffusion plate 120 is disposedon the first and second sub-light guide plates 11 and 16. In addition,at least one of the first to third light source parts 20, 26 and 29 ispositioned adjacent to each lateral side of the first and secondsub-light guide plates 11 and 16 in the first direction D1. Hereinafter,the structure of the elements will be described in more detail.

According to one embodiment of the invention, the first sub-light guideplate 11 has a plate shape. The first sub-light guide plate 11 isprovided at a first side thereof with a first incident surface 12A, andat a second side thereof opposing the first incident surface 12A with asecond incident surface 12B. In addition, the first sub-light guideplate 11 has a first exit surface 13 connected to the first and secondincident surfaces 12A and 12B, and a first opposite surface 14 oppositeto the first exit surface 13.

In addition, the second sub-light guide plate 16 has a plate shape. Thesecond sub-light guide plate 16 is provided at a first side thereof witha third incident surface 17A and at a second side thereof opposing thethird incident surface 17A with a fourth incident surface 17B. Inaddition, the second sub-light guide plate 16 has a second exit surface18 connected to the third and fourth incident surfaces 17A and 17B, anda second opposite surface 19 opposite to the second exit surface 18.

The first light source part 20 is provided between the first and secondsub-light guide plates 11 and 16. The first light source part 20includes a first printed circuit board 23, first light source units 21,and second light source units 22. The first printed circuit board 23longitudinally extends in the third direction D3 perpendicular to thefirst direction D1 and between the first and second sub-light guideplates 11 and 16. When viewed from the top, at least a portion of thefirst printed circuit board 23 may overlap with the first and secondsub-light guide plates 11 and 16. In addition, the first printed circuitboard 23 is parallel to the first exit surface 13.

The first and second light source units 21 and 22 are electricallyconnected to the first printed circuit board 23. In addition, the firstand second light source units 21 and 22 are alternately arranged on thefirst printed circuit board 23 along the third direction D3.

The traveling direction of the light generated from the first lightsource units 21 is different from the traveling direction of the lightgenerated from the second light source units 22. In more detail, whenviewed from the top, the light generated from the first light sourceunits 21 substantially travels in the first direction D1, as indicatedby the arrows in FIG. 2. As a result, the light generated from the firstlight source units 21 is supplied to the first sub-light guide plate 11through the first incident surface 12A. In addition, the light generatedfrom the second light source units 22 substantially travels in thesecond direction D2 opposite to the first direction D1, as indicated bythe arrows in FIG. 2, so that the light generated from the second lightsource units 22 is supplied to the second sub-light guide plate 16through the third incident surface 17A.

In detail, as shown in FIGS. 3A and 3B, the first light source units 21are inclined toward the first sub-light guide plate 11 and the secondlight source units 22 are inclined toward the second sub-light guideplate 16. In other words, emitting surfaces ES of the first light sourceunits 21 are inclined in opposition to the display panel 400 about thefirst incident surface 12A of the first sub-light guide plate 11, so anextension line of the normal line Nes of the emitting surfaces ES of thefirst light source units 21 extends to pass through the first oppositesurface 14 opposite to the first exit surface 13. Thus, the first lightsource units 21 supply the light to the first incident surface 12A insuch a manner that the light may be inclined in opposition to thedisplay panel 400.

In this manner, if the light is supplied to the first incident surface12A in a state in which the emitting surfaces ES of the first lightsource units 21 are inclined in opposition to the display panel 400, theintensity of the light traveling toward the diffusion member 30 throughand between the first and second sub-light guide plates 11 and 16 may bereduced, and the quantity of the light incident into the first incidentsurface 12A may be increased.

Similar to the first light source units 21, the emitting surfaces ES ofthe second light source units 22 are inclined in opposition to thedisplay panel 400 about the third incident surface 17A of the secondsub-light guide plate 16, so the extension line of the normal line Nesof the emitting surfaces ES of the second light source units 22 extendsto pass through the second opposite surface 19 opposite to the secondexit surface 18. Thus, the second light source units 22 supply the lightto the third incident surface 17A in such a manner that the light may beinclined in opposition to the display panel 400.

In more detail, as shown in FIG. 3B, the normal line Nes of the emittingsurfaces ES of the second light source units 22 may form an angle θ withrespect to the normal line Nin of the third incident surface 17A. Theangle θ may be, for example, in the range of 0°<θ<45°.

Referring again to FIG. 2, the second light source part 26 is locatedadjacent to the second incident surface 12B to supply the light towardthe first sub-light guide plate 11. The second light source part 26includes a second printed circuit board 24 and third light source units25. The second printed circuit board 24 longitudinally extends in thethird direction D3 along the second incident surface 12B. When viewedfrom the top, at least a portion of the second printed circuit board 24may overlap with the first sub-light guide plate 11. The third lightsource units 25 are electrically connected to the second printed circuitboard 24 and arranged on the second printed circuit board 24 in thethird direction D3. When viewed from the top, the light generated fromthe third light source units 25 substantially travels in the seconddirection D2 so that the light is supplied toward the first sub-lightguide plate 11 through the second incident surface 12B.

In detail, emitting surfaces ES of the third light source units 25 areinclined in opposition to the display panel 400 so that the light issupplied to the second incident surface 12B while being inclined towardthe first opposite surface 14.

The third light source part 29 is located adjacent to the fourthincident surface 17B to supply the light toward the second sub-lightguide plate 16. The third light source part 29 includes a third printedcircuit board 27 and fourth light source units 28. The third printedcircuit board 27 longitudinally extends in the third direction D3 alongthe fourth incident surface 17B. When viewed from the top, at least aportion of the third printed circuit board 27 may overlap with thesecond sub-light guide plate 16. The fourth light source units 28 areelectrically connected to the third printed circuit board 27 andarranged on the third printed circuit board 27 in the third directionD3. When viewed from the top, the light generated from the fourth lightsource units 28 substantially travels in the first direction D1 so thatthe light is supplied toward the second sub-light guide plate 16 throughthe fourth incident surface 17B.

In detail, emitting surfaces ES of the fourth light source units 28 areinclined in opposition to the display panel 400 so that the light issupplied to the fourth incident surface 17B while being inclined towardthe second opposite surface 19.

As described above, the light guide plate 10 receives the light from thefirst to third light source parts 20, 26 and 29, and the light incidentinto the light guide plate 10 is output to the diffusion plate 120through the first and second exit surfaces 13 and 18 due to reflectivepatterns (not shown) on the opposite surfaces 14 and 19 of the lightguide plate 10.

The diffusion member 30 includes polymethylmethacrylate (“PMMA”) orpolycarbonate (“PC”) and longitudinally extends in the third directionD3 to cover (e.g., overlap) the first light source part 20 between thefirst and second sub-light guide plates 11 and 16. In addition, whenviewed from the top, the diffusion member 30 is disposed on the firstand second sub-light guide plates 11 and 16 such that the diffusionmember 30 may partially overlap with a portion of the first and secondsub-light guide plates 11 and 16. The diffusion member 30 diffuses thelight, which is generated from the first light source part 20 andtravels toward the diffusion plate 120 through and between the first andsecond sub-light guide plates 11 and 16.

The first sub-light guide plate 11 may be expanded due to externalenvironmental factors, such as temperature or humidity. In this regard,the first sub-light guide plate 11 may be spaced apart from the firstlight source units 12 while interposing an air layer therebetween. As aresult, a portion of the light emitted from the emitting surface ES maynot be supplied to the first incident surface 12A, but travels towardthe diffusion plate 120 through and between the first and secondsub-light guide plates 11 and 16. However, the light traveled toward thediffusion plate 120 is diffused by the diffusion member 30, so that thedisplay quality of the display apparatus 500 (see, FIG. 1) may not bedegraded.

FIG. 4 is an enlarged cross-sectional view of another exemplaryembodiment of a light source part shown in FIG. 1 according to theinvention.

Referring to FIG. 4, the light source part 20A includes a printedcircuit board 650 and a light source unit 601. The light source unit 601may include a light source 630 generating the light, a lead frame 620having the light source 630 mounted thereon and connecting the lightsource 630 to the printed circuit board 650, and a housing 610 receivingthe light source 630 and the lead frame 620.

The light source 630 may be a light emitting diode including twoelectrodes receiving voltages having polarities different from eachother to generate the light according to the voltages applied to the twoelectrodes. In general, the emitting surface ES of the light source unit601 is the same as the emitting surface ES of the light source 630. Theemitting surface ES of the light source 630 is inclined toward theprinted circuit board 650. In addition, the light source unit 601 isinclined with respect to the printed circuit board 650, and theextension line of the normal line of the emitting surface ES crosses anextension surface of the printed circuit board 650.

Although not shown in FIG. 4, the lead frame 620 includes first andsecond lead frames connected to the two electrodes of the light source630, respectively, and spaced apart from each other. In FIG. 4, only oneof the first and second lead frames is drawn.

The lead frame 620 includes a first frame 620 a adjacent to the printedcircuit board 650 and parallel to the printed circuit board 650, and asecond frame 620 b extending from the first frame 620 a, having thelight source 630 mounted thereon. The first frame 620 a protrudes out ofthe housing 610 and makes contact with the printed circuit board 650 tosupport the light source unit 601 and to electrically connect the lightsource 630 to the printed circuit board 650. The second frame 620 b hasa recess and the light source 630 is mounted in the recess. A mountingsurface 621 of the recess for the light source 630 is not perpendicularto the printed circuit board 650, but inclined with respect to theprinted circuit board 650. In detail, the mounting surface 621 of therecess for the light source 630 is inclined toward the printed circuitboard 650.

The housing 610 includes a receiving part 610 a to receive the lightsource 630 and the lead frame 620, and a support part 610 bsubstantially perpendicularly extending from the receiving part 610 a tocover at least a portion of the lead frame 620. The support part 610 bsupports the lead frame 620. The receiving part 610 a may include anopening to expose a surface, which is opposite to the mounting surface621 of the recess for the light source 630 in the second frame 620 b.Since the surface, which is opposite to the mounting surface 621 of therecess for the light source 630 in the second frame 620 b, is exposed tooutside of the light source part 20A, heat generated from the lightsource 630 can be easily dissipated to the outside.

In addition, an outer surface of the receiving part 610 a may beparallel to the mounting surface 621 of the recess for the light source630 in the second frame 620 b. Referring to FIG. 4, the mounting surface621 of the recess for the light source 630 in the lead frame 620 and thereceiving part 610 a of the housing 610 are inclined toward the printedcircuit board 650 in the light emitting direction of the light sourceunit 601. Thus, if the light source 630 is mounted on the lead frame620, the emitting surface ES of the light source 630 is inclined towardthe printed circuit board 650.

The light source unit 601 may further include a transparent filler 640on the light source 630 and occupying an entire of the recess. Thetransparent filler 640 may include silicon.

FIG. 5 is an enlarged cross-sectional view of another exemplaryembodiment of a light source part shown in FIG. 1 according to theinvention. In the following description of the light source part 20Bshown in FIG. 5, the same reference numerals will be assigned to theelements and structures identical to those of the light source shown inFIG. 4 and detailed description thereof will be omitted in order toavoid redundancy.

Referring to FIG. 5, the lead frame 620 includes a first frame 620 aadjacent to the printed circuit board 650 and parallel to the printedcircuit board 650, and a second frame 620 b extending from the firstframe 620 a to mount the light source 630 thereon. The first frame 620 aprotrudes out of the housing 610 and makes contact with the printedcircuit board 650 to support the light source unit 601 and toelectrically connect the light source 630 to the printed circuit board650. The second frame 620 b has a recess and the light source 630 ismounted in the recess. A mounting surface 621 of the recess for thelight source 630 is not perpendicular to the printed circuit board 650,but inclined with respect to the printed circuit board 650. In detail,the mounting surface 621 of the recess for the light source 630 isinclined toward the printed circuit board 650.

The housing 610 includes a receiving part 610 a to receive the lightsource 630 and the lead frame 620, and a support part 610 bsubstantially perpendicularly extending from the receiving part 610 a tocover at least a portion of the lead frame 620 and to support the leadframe 620. Different from FIG. 4, the support part 610 b issubstantially perpendicular to the printed circuit board 650. In detail,the mounting surface 621 of the recess for the light source 630 in thesecond frame 620 b is inclined with respect to an outer surface of thesupport part 610 b.

Although the support part 610 b of the housing 610 is substantiallyperpendicular to the printed circuit board 650, the mounting surface 621of the recess for the light source 630 in the second frame 620 b of thelead frame 620 is inclined with respect to the outer surface of thesupport part 610 b. Thus, the light emitted from the light source 630 isinclined toward the printed circuit board 650. In addition, since thehousing 610 of the light source unit 601 is perpendicular to the printedcircuit board 650, the light source unit 601 can be easily mounted onthe printed circuit board 650.

FIG. 6A is a front perspective view of another exemplary embodiment of alight source unit shown in FIG. 1 according to the invention, and FIG.6B is a rear perspective view of the light source unit shown in FIG. 6A.

Referring to FIGS. 6A and 6B, the light source unit 600 includes thelight source 630 to generate the light, lead frames 720 and 620 to mountthe light source 630 thereon such that the light source 630 can beconnected to a printed circuit board (not shown), and the housing 610 toreceive the light source 630 and the lead frames 720 and 620 therein.

The light source 630 may be a light emitting diode including twoelectrodes receiving voltages having polarities different from eachother to generate the light according to the voltages applied to the twoelectrodes. In general, the emitting surface ES of the light source unit600 is the same as the emitting surface ES of the light source 630.

Although not shown in the drawings, as shown in FIGS. 4 and 5, theemitting surface ES of the light source 630 is inclined toward theprinted circuit board. In addition, the light source unit 600 isinclined with respect to the printed circuit board and the extensionline of the normal line of the emitting surface ES crosses an extensionsurface of the printed circuit board.

Referring again to FIGS. 6A and 6B, the lead frames 720 and 620 aredivided into first and second lead frames 720 and 620 connected to thetwo electrodes of the light source 630, respectively, and spaced apartfrom each other.

The first lead frame 720 includes a first frame 720 a adjacent to theprinted circuit board and parallel to the printed circuit board, and asecond frame 720 b extending from the first frame 720 a and connected tothe light source 630. The first frame 720 a and the second frame 720 btogether form a single unitary indivisible first lead frame 720, asindicated by the dotted line portions in FIGS. 6A and 6B. The secondlead frame 620 includes a first frame 620 a adjacent to the printedcircuit board and parallel to the printed circuit board, and a secondframe 620 b extending from the first frame 620 a to mount the lightsource 630 thereon. The first frame 620 a and the second frame 620 btogether form a single unitary indivisible second lead frame 620.

The first frames 720 a and 620 a of the first and second lead frames 720and 620 protrude out of the housing 610 and contact the printed circuitboard to support the light source unit 600 and to electrically connectthe light source 630 to the printed circuit board. In detail, the firstframes 720 a and 620 a protrude in the light emitting direction of thelight source unit 600 to support the light source unit 600.

The second frame 720 b of the first lead frame 720, which extends fromthe first frame 720 a of the first lead frame 720 and is substantiallyperpendicular to the first frame 720 a of the first lead frame 720, isconnected to one of the electrodes of the light source 630.

The second frame 620 b of the second lead frame 620 has a recess and thelight source 630 is mounted in the recess. A mounting surface 621 of therecess for the light source 630 is not perpendicular to the printedcircuit board 650, but inclined with respect to the printed circuitboard 650. In detail, the mounting surface 621 of the recess for thelight source 630 is inclined toward the printed circuit board 650 in thedirection of the emitting surface ES.

The housing 610 receives the light source 630 and the first and secondlead frames 720 and 620. The housing 610 has an opening to expose asurface 621 a opposite to the mounting surface 621 of the recess for thelight source 630 in the second frame 620 b of the second lead frame 620.Since the surface 621 a, which is opposite to the mounting surface 621of the recess for the light source 630 in the second lead frame 620, isexposed to outside of the light source unit 600, heat generated from thelight source 630 can be easily dissipated to the outside.

The second lead frame 620 may further include a third frame 620 c. Thethird frame 620 c is adjacent to the printed circuit board, parallel tothe printed circuit board and extends from the second frame 620 b of thesecond lead frame 620. The third frame 620 c protrudes in the directionopposite to the light emitting direction of the light source unit 600.In detail, the third frame 620 c protrudes in opposition to the firstframes 720 a and 620 a of the first and second lead frames 720 and 620to support the light source unit 600. The first frames 720 a and 620 aand the third frame 620 c support the light source unit 600 in the lightemitting direction of the light source unit 600 and in the directionopposite to the light emitting direction of the light source unit 600,so that the light source unit 600 can be effectively supported. Thefirst to third frames 620 a to 620 c together form a single unitaryindivisible second lead frame 620.

When viewed from the top, the area of the third frame 620 c is largerthan the sum of the areas of the first and second lead frames 720 and620 and the first frames 720 a and 620 a. In detail, when viewed fromthe top, the area of the first and second lead frames 720 and 620protruding in the light emitting direction may be smaller than the areaof the second lead frame 620 protruding in the direction opposite to thelight emitting direction. When the area of the third frame 620 c isincreased when viewed from the top, the light emitting direction of thelight source 630 may not be directed to the direction opposite to theprinted circuit board even if external force is applied to the lightsource unit 600.

According to an alternative embodiment of the invention, the firstframes 720 a and 620 a of the first and second lead frames 720 and 620may not protrude from the housing 610 in the light emitting direction ofthe light source 630.

Similar to FIGS. 4 and 5, the mounting surface 621 of the recess for thelight source 630 in the second frame 620 b of the second lead frame 620in FIGS. 6A and 6B is inclined toward the printed circuit board in thelight emitting direction of the light source unit 600. Thus, when thelight source 630 is mounted on the second lead frame 620, the emittingsurface ES of the light source 630 is inclined toward the printedcircuit board.

FIG. 7A is a front perspective view of still another exemplaryembodiment of a light source unit shown in FIG. 1 according to theinvention, and FIG. 7B is a rear perspective view of the light sourceunit shown in FIG. 7A. In the following description of the light sourceunit shown in FIGS. 7A and 7B, the same reference numerals will beassigned to the elements and structures identical to those of the lightsource shown in FIGS. 6A and 6B and detailed description thereof will beomitted in order to avoid redundancy.

Referring to FIGS. 7A and 7B, the light source unit 700 includes thelight source 630 to generate the light, the lead frames 720 and 620 tomount the light source 630 thereon such that the light source 630 can beconnected to a printed circuit board (not shown), and the housing 610 toreceive the light source 630 and the lead frames 720 and 620 therein.The lead frames 720 and 620 are divided into the first and second leadframes 720 and 620 connected to the two electrodes of the light source630, respectively, and spaced apart from each other.

Different from FIGS. 6A and 6B, the recess of the second frame 620 b ofthe second lead frame 620 extends to the third frame 620 c in FIGS. 7Aand 7B. In other words, the surface 621 a, which is opposite to themounting surface 621 for the light source 630 in the second frame 620 bof the second lead frame 620 is connected to an upper surface of thethird frame 620 c and exposed to an outside of the light source unit700. The surface 621 a, which is opposite to the mounting surface 621for the light source 630 in the second frame 620 b of the second leadframe 620, may dissipate heat generated from the light source 630, sothe heat dissipation efficiency can be improved by effectivelyincreasing the area of the surface 621 a. The first to third frames 620a to 620 c together form a single unitary indivisible second lead frame620, as indicated by the dotted lines in FIGS. 7A and 7B.

Similar to FIGS. 4 and 5, the mounting surface 621 of the recess for thelight source 630 in the second frame 620 b of the second lead frame 620in FIGS. 7A and 7B is inclined toward the printed circuit board in thelight emitting direction of the light source unit 600. Thus, when thelight source 630 is mounted on the second lead frame 620, the emittingsurface ES of the light source 630 is inclined toward the printedcircuit board.

FIG. 8 is a cross-sectional view showing the light source unit 700 ofFIGS. 7A and 7B mounted on a printed circuit board.

A solder 800 overlaps the first frame 620 a and the third frame 620 c ofthe light source unit 700, and the light source unit 700 is electricallyconnected to the printed circuit board PCB through the solder 800. Thesolder 800 is not only coated on the first frame 620 a and the thirdframe 620 c, but is also coated on a portion of the second frame 620 bof the second lead frame 620 to overlap a portion of the surface 621 aopposite to the mounting surface 621 for the light source 630 in thesecond frame 620 b of the second lead frame 620. The surface 621 aopposite to the mounting surface 621 for the light source 630 maydissipate the heat generated from the light source 630 to the outside ofthe light source unit 700. Since the solder 800 covers at least aportion of the surface 621 a opposite to the mounting surface 621 forthe light source 630, the heat can be dissipated through the solder 800and the heat dissipation efficiency can be further improved.

FIG. 9 is an exploded perspective view showing another exemplaryembodiment of the relationship among the first to third light sourceparts, the light guide plate and the diffusion plate according to theinvention, and FIG. 10 is a side cross-sectional view showing anexemplary embodiment of the light source part of FIG. 9. In thefollowing description of FIG. 9, the same reference numerals will beassigned to the elements and structures identical to those of FIG. 2 anddetailed description thereof will be omitted in order to avoidredundancy.

Referring to FIGS. 9 and 10, a backlight unit 201 includes the firstlight source part 20, a second light source part 56, a third lightsource part 59, the light guide plate 10 including the first sub-lightguide plate 11 and the second sub-light guide plate 16, the diffusionmember 30, and the diffusion plate 120.

The light guide plate 10 includes the first and second sub-light guideplates 11 and 16 spaced apart from each other and arranged in the firstdirection D1. The diffusion plate 120 is disposed on the first andsecond sub-light guide plates 11 and 16. The first light source part 20is provided between the first and second sub-light guide plates 11 and16. The first light source part 20 includes the first printed circuitboard 23, the first light source units 21, and the second light sourceunits 22. When viewed from the top, the light generated from the firstlight source units 21 substantially travels in the first direction D1 sothat the light is supplied to the first sub-light guide plate 11 throughthe first incident surface 12A. In addition, the light generated fromthe second light source units 22 substantially travels in the seconddirection D2 opposite to the first direction D1, so that the light issupplied to the second sub-light guide plate 16 through the thirdincident surface 17A.

Referring to FIGS. 9 and 10, the second light source part 56 is disposedadjacent to the second incident surface 12B to supply the light towardthe first sub-light guide plate 11. The second light source part 56includes a second printed circuit board 54, a first inclined structure53 and third light source units 55.

The second printed circuit board 54 longitudinally extends in the thirddirection D3 along the second incident surface 12B while facing thesecond incident surface 12B. The first inclined structure 53 faces thethird light source units 55 while interposing the second printed circuitboard 54 therebetween. In the illustrated exemplary embodiment, forinstance, the first inclined structure 53 has a prism shapelongitudinally extending in the third direction D3. The first inclinedstructure 53 allows the second printed circuit board 54 and the thirdlight source units 55 to be inclined in the direction opposite to thedisplay panel 400 (see, FIG. 1), that is, toward the opposite surface 14of the first sub-light guide plate 11.

The third light source units 55 are electrically connected to the secondprinted circuit board 54 and arranged on the second printed circuitboard 54 in the third direction D3. When viewed from the top, the lightgenerated from the third light source units 55 substantially travels inthe second direction D2, so the light is supplied to the first sub-lightguide plate 11 through the second incident surface 12B.

In detail, each third light source unit 55 includes a light source 55 a,first and second lead frames 55 b and 55 c and a housing 55 d. The firstand second lead frames 55 b and 55 c are spaced apart from each otherand parallel to the printed circuit board 54. The light source 55 a ismounted on the second lead frame 55 c, and the first and second leadframes 55 b and 55 c are electrically connected to the light source 55 athrough a conductive line CL, so that the printed circuit board 54 iselectrically connected to the light source 55 a.

The housing 55 d receives the first and second lead frames 55 b and 55 cand the light source 55 a therein. A transparent filler 55 e may beprovided in the housing 55 d.

The third light source part 59 is disposed adjacent to the fourthincident surface 17B to supply the light toward the second sub-lightguide plate 16. The third light source part 59 includes a third printedcircuit board 57, a second inclined structure 60 and fourth light sourceunits 58.

The third printed circuit board 57 longitudinally extends in the thirddirection D3 along the fourth incident surface 17B while facing thefourth incident surface 17B. The second inclined structure 60 faces thefourth light source units 58 while interposing the third printed circuitboard 57 therebetween. In the illustrated embodiment, for instance, thesecond inclined structure 60 has a prism shape longitudinally extendingin the third direction D3. The second inclined structure 60 allows thethird printed circuit board 57 and the fourth light source units 58 tobe inclined in the direction opposite to the display panel 400 (see,FIG. 1), that is, toward the opposite surface 19 of the second sub-lightguide plate 16.

The fourth light source units 58 are electrically connected to the thirdprinted circuit board 57 and aligned on the third printed circuit board57 in the third direction D3 and parallel to each other. When viewedfrom the top, the light generated from the fourth light source units 58substantially travels in the first direction D1, so the light issupplied to the second sub-light guide plate 16 through the fourthincident surface 17B.

Although the exemplary embodiments of the invention have been described,it is understood that the invention should not be limited to theseexemplary embodiments but various changes and modifications can be madeby one ordinary skilled in the art within the spirit and scope of theinvention as hereinafter claimed.

What is claimed is:
 1. A display apparatus comprising: a first sub-lightguide plate comprising a first incident surface and a first exitsurface, the first sub-light guide plate guiding a first light incidentinto the first incident surface toward the first exit surface; a secondsub-light guide plate comprising a third incident surface and a secondexit surface, the second sub-light guide plate guiding a second lightincident into the third incident surface toward the second exit surface,wherein the first sub-light guide plate and the second sub-light guideplate are spaced apart from each other and aligned in a first direction;a display panel disposed on the first sub-light guide plate and thesecond sub-light guide plate and configured to display an image; and afirst light source part disposed between the first sub-light guide plateand the second sub-light guide plate and including first light sourceunits configured to generate the first light and second light sourceunits configured to generate the second light, wherein the first lightsource units and the second light source units are inclined in differentdirections from each other.
 2. The display apparatus of claim 1, whereinthe first light source units are inclined toward the first sub-lightguide plate and the second light source units are inclined toward thesecond sub-light guide plate.
 3. The display apparatus of claim 2,wherein the first light source units and the second light source unitsare alternately arranged along a third direction perpendicular to thefirst direction.
 4. The display apparatus of claim 2, wherein the firstsub-light guide plate further comprising a first opposite surface whichis opposite to the first exit surface, wherein the second sub-lightguide plate further comprising a second opposite surface which isopposite to the second exit surface, wherein the first light sourceincludes a first emitting surface inclined with respect to the firstincident surface of the first sub-light guide plate, and an extensionline of a normal line of the first emitting surface passes through thefirst opposite surface of the first sub-light guide plate. wherein thesecond light source includes a second emitting surface inclined withrespect to the third incident surface of the second sub-light guideplate, and an extension line of a normal line of the second emittingsurface passes through the second opposite surface of the secondsub-light guide plate.
 5. The display apparatus of claim 4, wherein thefirst sub-light guide plate further comprising a second incident surfaceopposite to the first incident surface, wherein the second sub-lightguide plate further comprising a fourth incident surface opposite to thethird incident surface, the display apparatus further comprising: asecond light source part including a third light source units configuredto generate a third light and located adjacent to the second incidentsurface to supply the third light toward the first sub-light guideplate; a third light source part including a fourth light source unitsconfigured to generate a fourth light and located adjacent to the fourthincident surface to supply the fourth light toward the second sub-lightguide plate.
 6. The display apparatus of claim 4, wherein the thirdlight source units are inclined toward the first sub-light guide plateand the fourth light source units are inclined toward the secondsub-light guide plate.
 7. The display apparatus of claim 6, wherein thefirst light source units and the fourth light source units are inclinedin a same direction from each other and the second light source unitsand the third light source units are inclined in a same direction fromeach other.
 8. The display apparatus of claim 6, wherein the firstsub-light guide plate further comprising a first opposite surface whichis opposite to the first exit surface, wherein the second sub-lightguide plate further comprising a second opposite surface which isopposite to the second exit surface, wherein the third light sourceincludes a third emitting surface inclined with respect to the secondincident surface of the first sub-light guide plate, and an extensionline of a normal line of the third emitting surface passes through thefirst opposite surface of the first sub-light guide plate. wherein thefourth light source includes a fourth emitting surface inclined withrespect to the fourth incident surface of the second sub-light guideplate, and an extension line of a normal line of the fourth emittingsurface passes through the second opposite surface of the secondsub-light guide plate.